Good Orgasmic Pelvic Contraction Study from 1982 - A Journal Article I Read

I was starting to do a summary (in the ol' A Journal Article I Read Series) of some other article, but in it I saw it referenced that this article claimed to have found women who orgasmed but had no rhythmic pelvic muscle contractions. So, obviously, I wanted to check it out, and obviously it wasn't on the stupid site that I stupidly pay a monthly fee to, and obviously I had to pay 40 stupid bucks to get it...cause 1. I didn't want to deal with travelling to a college library searching through the stacks or 2. trying to ask my local library to get me access, because they always give me side eye and sigh a lot and it takes at least 2 week. So, anyway, I got it and it's here for you. I don't mind sharing if you need it. Anyway - here's my detailed, but hopefully not too detailed, summary of the following article...with a little of my personal thoughts at the end.

The female orgasm: pelvic contractions. Bohlen JG, Held JP, Sanderson MO, Ahlgren A. Arch Sex Behav. 1982 Oct;11(5):367-86.

My intro / super quick summary
So, very quickly, this 1982 article took 11 women and put probes in their anus and vagina to record muscle contractions while these women 1. relaxed for 5 minutes, then 2. stimulated their clits to orgasm. Each woman did it 3 times on 3 different occasions. When they perceived the beginning of their orgasm, they pushed a button and then pushed it again when they felt their orgasm had finished. For 6 of those women, a set of steady, regular muscle contractions were recorded followed by a set of irregular muscle contractions during their perceived orgasm. For 3 women, a set of regular muscle contractions were recorded during their perceived orgasm, but no subsequent irregular contractions. For 2 of the women, no regular muscle contractions were recorded during their perceived orgasm at all, and the recordings between their 2 button pushes (their perceived orgasm) couldn't really be differentiated from the readings before their perceived orgasm while masturbating.

So, this article is important for a couple reasons. 1. it further corroborated what has been anecdotally known for a long time, and what Master's and Johnson and the small amount of physiologic research between this article and M&J had said - that orgasm is accompanied by rhythmic pelvic muscle contractions. However, it found some different patterns for the rhythmic muscle contractions than have been described so far, and got more details about timing and quality of the muscle contractions. It also obtained information about when orgasm was perceived by women versus what was happening to them physiologically.

It also identified 2 women who perceived having an orgasm, but did not have discernible pelvic muscle activity associated with that orgasm. So, this article brings up the questions - did these women have an unique physiological experiences that was not detected physiologically, or did these women experience something non-physical....and if it can not be described physically what is it and how should it be discussed alongside the physiological orgasm?

So, I think this is a useful piece of the lady-gasm study puzzle. It's actually quite a good one too. Here's the deets.


  • Association of women's pelvic contractions with orgasm has been well documented since at least 1876. Direct observation, palpation, intravaginal air chamber pressure measurements, surface electromyography, direct electromyography, and unspecified methods have all been used for detection. However, as yet, only number of and frequency of contractions have yet been reported. Now (remember this is 1982) with computer operated data-collection systems things like" muscular force and exertions, frequency, waveform, and overall temporal pattern can be directly recorded and automatically compute."
  • "The purpose of this paper is to elucidate some of these physical characteristics in order to lay a better foundation for understanding the mechanism of pelvic muscular activity during sexual response."


  • recruited out of human sexuality classes at University of Minnesota or conversations with previous subjects
  • 11 subjects chosen between 24 and 33 years old
  • none have ever given birth
  • all were self-defined mentally, physically, and sexually healthy, on some type of birth control, and had no abnormal finding from their pelvic exam
  • 7 subjects have "regular" periods and 4 have "usually irregular" periods
  • before the physical recordings, all the women visited the lab 4 different time to tour the facilities, take several different sexual and psychological surveys, and give a sexual history
  • each signed informed consent, were informed of the aims and methods of the experiment, and each was assured she could discontinue her involvement at any time
  • all were voluntary, unpaid participants
  • "Manual self-stimulation was a common means of sexual gratification for all of the subjects. In the week preceding subjects' sessions, the number of masturbatory experiences to orgasm averaged 2.3 times, and total sexual outlets to orgasm averaged 3.8 times. None of them had orgasms during the 24 hours before a recording session, except one session of one subject."

  • "Vaginal and anal pressure were collected on each subject during three separate masturbation sessions. The format was the same for each session. The subject lay supine on the bed. After the vaginal and anal probes were inserted, the subjects were left in privacy. Her resting pressures were recorded during 5 minutes of relaxation. She was then instructed by intercom to begin clitoral stimulation and continue to orgasm. Although the probes limited the possible masturbation techniques, subjects reported that the stimulation was typical and replicable from one session to the next. Subjects had been instructed to signal as precisely as possible with an event marker button the perceived start and end of orgasm. Recording continued for 5 minutes of relaxation after orgasm while vaginal and anal pressures returned to baseline."
  • The probes were sterilized - so don't worry. They detail that out too.
  • Heart beat, respiratory rates, vaginal and anal blood volume and blood pulse, skin conductance response were also measured during the sessions
  • The subjects also completed subjective questionnaires before and after the sessions, but the results of those are not included in this study.

  • They used probes to quantify pressure changes. It could be set specifically for use in the anus or use in the vagina. (Bohlen and Held 1979). They were placed by researchers in a standardized placement. 
  • "the processed signals were digitized by a computer and the data were stored on flexible diskettes." (I like the quaintness of that sentence, don't you?)

  • Several parameters of the pelvic contractions during orgasm were calculated
  • Abrupt pressure increases with peaks above a specified minimum amplitude were located, and these "contractions" were then numbered consecutively, and the following parameters were calculated to describe each: contraction amplitude, area, net area, and intercontraction interval
  • a total number of contractions during orgasm was counted
  • The number of seconds between the stop and start signals were calculated as duration of subjective orgasm
  • For the 9 subjects showing regular contractions, these parameters were averaged over each subject's three sessions


Orgasmic contractions: regular contractions

  • "...nine of the eleven subjects had a series of regular contractions that were clearly distinguished from the steady tension during relaxation and the irregular and arrhythmic pressure changes during early stimulation."
  • "Intervals between contraction peaks were shortest at first and gradually lengthened."
  • "About 7-13 contractions occurred over a span of 5 to 14 seconds."
  • "Because of its abrupt onset and termination, uniform wavelength, and linearly increasing intervals, this initial series of contractions has been designated as the series of regular contractions(Bohen et al., 1980). "

Orgasmic contractions: further irregular contractions
"For six of the nine women, the perceived orgasms continued past the series of regular pelvic contractions. The uniformity of waveform, amplitude and interval increase characteristics of the regular contractions ceased during those subsequent contractions. Pressure still rose sharply at the onset of a contraction, but the relaxation back to baseline was more gradual than in the series of regular contractions. Intervals between contractions were variable. The non-uniform contractions have been designated irregular contractions (Bohen et al., 1980)"

Lack of regular contractions during orgasm
"Two of the subjects showed a marked difference in orgasm record. Although they signaled orgasm, their records did not show a series of regular contractions during any of the three recorded sessions. Instead, the pressure records showed only gradually fluctuating pressure and nonuniform contractions. consequently, the portion of records during reported orgasm could not be distinguished from those prior to orgasm."

Vaginal and anal contractions
  • "Pressures recorded simultaneously within the vagina and anus showed synchronized contractions at orgasm."
  • The wave forms of the anal vs. vaginal contractions had different specific qualities: for instance, baseline anal pressure was higher, the anal contractions had greater amplitude and had a greater range of variation during contractions

Contraction Pattern Types
  • "Each woman's contraction pattern was highly similar from one session to the next. Patterns among the eleven subjects were discernible as three discrete types." 
  1. Type I - the orgasm signaled by the woman included the series of regular contractions without the subsequent irregular ones. (3 women) (Average Length of Type I orgasms: 13.1 seconds)
  2. Type II - the orgasm signaled by the woman included the series of regular contractions and also additional irregular ones afterward (6 women) (Average Length of Type II orgasms: 50.6 seconds)
  3. Type IV - Records of the two remaining subjects consistently did not reveal a series of regular contractions during signaled orgasm (Average Length of Type IV orgasms: 24.4 seconds)
  • "(Type III contraction pattern, of a divided regular series, had been found only in men so far,)"
  • "all type II orgasms were longer than all type I orgasms."
Average Characteristics of Women's Anal Contractions During Orgasm of Three Pattern Types (Bohlen et al., 1982)

Contraction Parameters
All the contraction parameter summaries presented are from anal measurements. This is used instead of the vaginal data because:

  1. anal had more precisely defined peaks
  2. anal data was free of artifacts caused by pressure from fingers during the stimulation that sometimes appeared in the vaginal data
  3. anal data can be directly compared to data recorded by the same method in males

"Calculation of contraction parameters began with the onset of the series of regular contractions, regardless of when the subject signaled the start of orgasm. For only one subject, however, did the series always begin before orgasm was signaled. Contraction parameters were not calculated for the two subjects whose records did not reveal regular contractions."

"For subjects with pattern type I, the average interval between the first and the second regular contraction was about 0.5 seconds, whereas this interval was 0.9 seconds for subjects with pattern type II. For both groups, the intervals increased at about the same rate."

"Amplitude of anal contractions at orgasm in both types I and II increased for the first five or six contractions before leveling off and then decreasing. The irregular contractions that follow in the type II pattern, show no recognizable progression."

The article speaks in more detail about specific mathematical qualities of the contraction graphs (that you can go check out if you are particularly interested). However, one thing that is discussed is that differences in base anal pressure among each woman can be blamed largely for a large dispersion line in the amplitude, contraction area, and net area increases.

Perception of orgasm start
  • The moment the woman pushed the button to signal her start of orgasm in relation to the start of regular orgasmic contractions ranged from about 4 seconds before to 1.5 seconds after the first regular contraction. 
  • The perception of orgasm start did not have a discernible difference between women with type I and type II patterns
  • There was some variation in perception of orgasm start for each woman in terms of the 3 sessions she had.  
  • 4 subjects had a range  in perception among sessions of about 1 second
  • The remaining 5 women had a broader range of signalling the start of perceived orgasm, with one woman having a range greater than 5 seconds


Comparison of anal and vaginal contractions
  • "Results showed that anal and vaginal pressures responded synchronously when contractions occurred during orgasm."
  • The authors pointed out that although other authors (like Masters and Johnson) had reported anal sphincter contractions along with the vaginal contractions, they hadn't stated that the contractions were synchronous, and in fact reported that they largely occurred only in intense orgasms and included fewer contractions. 
  • It was also noted that the differences of resting pressure and orgasmic contraction data received from the vagina versus the anus indicates some differences in physiological properties of the respective muscles.
Physiological typology of orgasm
  • Creating distinct types of contraction patterns as has been done in this paper has only been done in other papers thus far using self-reported perceptions from women. (Masters and Johnson identified different patterns of how a person moved between plateau level arousal through orgasm and back down to pre-arousal conditions, but did not identify specific types based on contractions qualities - I'm saying this not the paper). So this is important in that it is using actual physical, observed properties to categorize.
  • The authors also point out that all the women in this study orgasmsed through clitoral stimulation and so this article has nothing to say about the controversy between "clitoral" and "vaginal" orgasms.
  • I'm going to quote a large block of text next because I think these authors do a fantastic job of asking the important questions that this research clearly brings to light.
"Individuals were assigned to pattern types based on the presence or absence of a series of regular contractions and of additional irregular contractions during the signaled orgasm. Pressure waveforms of the irregular contractions were less sinusoidal and less regular in amplitude than those in the series of regular contractions. These irregular contraction waveforms were similar to those of the voluntary contractions performed before subjects were instructed to begin clitoral stimulation. In both the irregular and the voluntary waveforms, amplitudes were large and the pressure return to baseline was initially rapid, but then slow. Do the similarities between voluntary contractions and irregular contractions during orgasm mean that some women have control over irregular contractions? Might irregular contractions be the result of continued voluntary stimulation beyond the initial series of regular contractions? If a woman stopped stimulation at the end of the initial series of regular contractions, would the irregular contractions not occur and her perception of orgasm end? Or, if a woman who had only regular contractions continued stimulation beyond the initial series, would irregular contractions occur, thereby extending her perception of orgasm? Do some women learn during their early masturbatory experiences that they can continue stimulation beyond the initial series of regular contractions and thereby extend heir perception of orgasm? Or, instead, do women have an inherent pattern type, and, through their masturbatory experiences, develop toward that capacity? These questions suggest the need for further physiological and developmental data collection and analysis." 

"Two of the subjects did not demonstrate the distinct muscular evidence of orgasm that the other nine did. During none of their orgasms did the initial series of regular contractions occur. Were these subjects interpreting some less pronounced change as orgasm? Should orgasm be defined by what is perceived or reported, or by physiological criteria? At this early stage in recording pelvic muscular activity, we are not yet prepared to conclude that physiological characteristics are more valid than self-reported perceptions for identifying orgasm. At least until more data are collected, especially of the ontogeny of contraction patterns, we will continue our analysis of physiological changed based on subjects' self-defined orgasm."
  • "Contraction patterns types I and II reported here have also been found in male subjects recorded intra-anally at orgasm during self-stimulation (Bohlen et al., 1980). Among eleven men, six had type I pattern, four had type II, and one exhibited a double series of regular contractions (type III), not yet recorded in any women. The number of subjects is too small to conclude that there are any differences in incidence of pattern type between men and women."
Comparison with other data
  • Generally the average number of contractions during orgasm match between this study (18 - that includes regular contractions and the irregular ones for those that had them) and others done before (they note studies showing 8, 10, 20, 3-5 and 10-15 contractions during female orgasm). However it's hard to compare because other studies don't discern between contraction patterns.
  • "The data from this study do not show the extreme within-subject variability in number of contractions during orgasm reported by Masters and Johnson. Also, in contrast to Masters and Johnson (1966), no correlation was found between number of contractions and level of satisfaction, perceived intensity, or sexual gratification (Bohlen et al., 1982)."
  • "Duration of signaled orgasm among subjects in the present study ranged from 7.4 to 107 seconds."
  • Few other studies have reported perceived orgasm length, but against the ones that have at least alluded to it, the 36 second average length of orgasm reported in this study was a bit long.
  • The linear increment of time between each contraction during the regular intervals was a consistent characteristic in this study.  Using a equations that I don't really understand, the authors compare this finding to previous studies and found it matched others - particularly a previous study about male orgasm by this author, but did not match what can be inferred from Masters and Johnson - although it's actually a bit unclear what M&J meant by their discussion of this so it is hard to compare or understand the discrepancy.  (Personally, it makes sense to me to put more value on this study for these specific details of orgasmic contraction qualities because M&J likely gained a large amount of their data from direct observation of vaginal musculature and any waveform readings were likely done externally. So this study is a good expansion of what M&J started. Their measure of both vaginal and anal contractions internally give a better picture of the pelvic muscle activity during orgasm).
Perceived start and empirical onset of orgasm
  • The perceived start of orgasm compared to the start of regular contractions is varied among studies, but the authors rightly ask as yet unanswerable questions about why this might be. Is it that people merely perceive and/or interpret the same thing differently? Do some people have a higher sensory threshold? Is something physical happening for some and not others that we don't yet detect? 
Perspective of physiological research

"Of what value is the quantification of pelvic contractions during orgasm? Simultaneous recording of the many physiological variables during sexual response reveals that only anal and vaginal pressures provide distinct physiological evidence of orgasm. Although other variable (e.g., hear rate) change rapidly during sexual response in a pattern similar to that during nonsexual arousal, anal and vaginal pressure in the series of regular contractions is unmistakably different from the pressure recorded both before and after orgasm. The regular series has an abrupt onset near the perceived start of orgasm and has a unique pattern of waveforms that is dissimilar to that during nonsexual arousal and that cannot be produced voluntarily. However, the series of regular contractions is not the sine qua non of orgasm (two of the eleven subjects did not produce regular contractions during their signaled orgasms)."

The authors finish the paper by pointing out that quantification of pelvic contractions are important because:
  • they can be compared among subjects and be related to subjects' perceptions
  • they can be used to identify a subjects pattern type which can help determine if pattern-type correlates to other things
  • the data can allow discernment  between contraction patterns which can help make comparisons from one study to the next in a variety of ways

My final thoughts
I think this is a really fabulous paper. It lays out physiological data about orgasm and does not overstep its boundaries in making conclusions. It builds upon the data M&J put out there about orgasmic muscular contractions, expanding on it, using better tools, and giving more detailed, specific information. It reinforces the understanding that orgasm is deeply related to the onset of regular pelvic muscle contractions, but breaks it down, identifying contraction patterns that are comparable even between the sexes. It also brings up the important question of whether women (cause only women so far have shown this) who say they have orgasmed but do not exhibit regular pelvic contractions, are orgasming? It is clear that they are experiencing something physically different during their orgasm than those who do exhibit regular contractions, but is it best viewed as "another type of orgasm" or as a lack of orgasm. As I have often said, until researchers find a way to physically identify and characterize this "other type of orgasm," I find it hard to categorize that experience in the same bucket as one that exhibits the clearly identifiable physical reaction of regular pelvic contractions . Wouldn't it be awesome to use the two women in this study and run experiments to see if they have similar brain activity and hormone release as women who have the contractions? Do their bodies go back to pre-arousal levels after they orgasm as quickly as the other women? How many other women are out there who do not show any orgasmic contractions when they claim orgasm? Are there any men? Is there something in common that would put them all in that category?

Ah - much work to be done - work that has absolutely not been done even though it is completely possible for it to have been done.  This paper is a great start though...too bad such little follow-up has been done in the 30 years since it was published.

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